Blueprints

class helix.blueprint.Blueprint(build_name, components=None, transforms=None, *args, **kwargs)

A common base class for all blueprints.

abstract property callsites

A list of valid callsites which Components may use.

A good practice is to define these as constants on the Blueprint class as well so they may be referenced directly by components and don’t rely on matched strings.

sane()

Ensure the current list of components is sane.

This method is optional and allows the developer to define additional constraints on the components supported by this Blueprint. This method should raise exceptions if the build is not sane.

property tags

Returns the union of all tags involved in this blueprint.

Simply aggregates and dedups all tags on Components and Transforms.

property functions

Aggregate all functions from included Components.

property calls

Aggregate all calls from included Components.

abstract generate(directory)

Generates a source directory from an interable of components.

The components passed to this class wll be finalized prior to calling this so that their source code is readily available. This function is responsible for writing configured components to the target output directory.

Parameters

directory (str) – A directory to write the resulting generated source code - you may assume that this directory already exists and is writable.

Returns

A list of generated source files.

Note

Component order matters here - this is the order in which calls and includes will be inserted into the generated source so if this is important you should make sure the order of components passed to this function is what you want.

transform(type, targets)

Applies all Transforms of a given type.

Parameters

• type (str) – The type of transform to apply.

• targets (str) – A list of targets to transform.

abstract compile(directory, options)

Compiles the target directory.

Compiles a directory generated with generate, applies any artifact transformations, and returns a list of build artifacts.

Parameters

• directory (str) – A directory with generated source code.

• options (dict) – An optional dictionary of additional build options that should be respected by this function. This will contain things like stdout, stderr and propagate for display options.

Returns

A list of built artifacts.

Note

In practice this may frequently just be a bunch of calls to os.system to invoke the target build system of this Blueprint.

build(directory, options=None)

Fully builds this Blueprint.

Generates code from Components, applies source Transforms, compiles code, and applies artifact Transforms.

Parameters

• directory (str) – A directory to write the resulting generated source code.

• options (dict) – An optional dictionary of additional build options that should be used by compile.

Returns

A list of built and transformed artifacts.

classmethod install(verbose=False)

Install all dependencies.

This reruns dependency installation regardless of if it has been installed already. This should be safe because of the requirement that dependency installation methods be repeatable but can be inefficient. Users can check the installed() method to determine if the installation should be rerun.

Parameters

verbose (bool) – Verbosity.

classmethod installed()

Check if all dependencies have been installed.

Returns

True if all dependencies have been installed already, and False otherwise.

abstract property name

A simple name.

Names should consist of [a-z-]. Make use of the optional verbose_name property if you would like a pretty-printable version of this name.

abstract property type

A short type descriptor.

This should be set to some constant (a short string) defined in some common location.

abstract property verbose_name

Optional verbose name for pretty printing.

By default this will just return name.

abstract property version

A version number.

This should be a string using Semantic Versioning.

Included Blueprints